Just about everyone agrees that 2013 was not a good year for President Obama. His job approval plummeted as the Obamacare rollout cratered. His oft-promised pivot to Asia was as much of a dud as his oft-promised pivot to the economy.

But it must also be said that the Republican politicians who have been touted as possible successors to the 44th president didn't have sparkling years either. Each has encountered a setback to his prospects for either the Republican nomination or as a general election candidate.

The obvious case in point is New Jersey Gov. Chris Christie. The liberal media, ever eager to discredit a Republican who polls well, have lavished thousands of words over whether he knew about a shutdown of a few lanes to the George Washington Bridge.

There's a lot of overkill here and no smoking gun. But how a potential president governs is a legitimate story, even if the same media didn't ask that question much about Obama.

A clearer setback was suffered by Texas Sen. Ted Cruz. He did more than anyone else to spur the two-week October government shutdown by demanding that Obamacare be defunded.

His argument -- that Obamacare would be too popular to repeal once it went into effect and people started getting subsidies -- has been sharply undercut by the fiasco of the rollout. Obamacare is more unpopular than ever, and there's no longer significant appetite among House Republicans for another shutdown.

Kentucky Sen. Rand Paul has made some progress in advancing a moderate and salable version of his father Ron Paul's libertarian policies. His opposition to an assertive foreign policy and support of tax and spending cuts are not necessarily disqualifying.

But he has had some setbacks too -- the revelation that a top staffer was a Confederate States sympathizer, some instances of plagiarism in speech texts, his comparison of leaker Edward Snowden to Martin Luther King, his unwillingness to repudiate his father's comment that the 9/11 attacks were "blowback for decades of U.S. intervention in the Middle East."

Two Republicans who made prominent speeches at the 2012 Republican National Convention have taken stands that could hurt them with Republican primary voters and caucus-goers.

Marco Rubio's leadership role on the Senate immigration bill providing for legalization and a path to citizenship for illegal immigrants evokes rage from many vocal Republican conservatives, even though it polls well among the larger voting public.

And vice presidential nominee Paul Ryan's budget deal with Democratic Sen. Patty Murray angered many fiscal conservatives who decried its increase in the airline passenger fee and cuts in inflation adjustments for some military retirees.

But Jindal's job approval has plunged, and both Walker and Kasich face serious reelection challenges this year.

If potential Republican nominees have had setbacks or made little progress, so have potential Democrats.

Hillary Clinton, leading by a wide margin in primary polls, could -- and should -- face questions on whether she and the State Department failed to take steps that would have prevented the death of Ambassador Chris Stevens and three other Americans in Benghazi.

Joe Biden, praised often by the president, was nonetheless called consistently wrong on foreign policy by his administration colleague, former Defense Secretary Robert Gates.

Martin O'Malley has raised taxes in Maryland -- maybe not a problem in a Democratic primary -- and has seen his Obamacare health exchange collapse.

Andrew Cuomo has suggested that those who oppose abortion, gun control and same-sex marriage have no place in his New York. But he'll need some of their votes to win a general election.

Former Montana Gov. Brian Schweitzer talks a good populist game. But is America ready for another untested leader?

Setbacks can be overcome. But both Republicans and Democrats have a problem if they want to be serious candidates in the 2016 cycle.

Democrats must defend and promise to advance big government programs even in the wake of the Obamacare fiasco.

Republicans must present alternative policies that address today's America and not just rehash the 1980 Reagan platform.

Neither party's potential nominees have made major advances on those fronts. Let's see if they do.